If they work anything like their jackets you'll love them!
I have a Milwaukee heated fluorescent and reflective jacket. Runs on a single m12 battery. It will sweat you out on high in 0 degree weather. Great coat. Held up ok after 2 winters in the mine. It's a little rough this year, but still works great, just has a few seams that are opening up. I can't find a replacement like it. All they have now are like fleece material. This is vinyl.